LA3161
Monolithic Linear IC
2-Channel Preamplifier
for Car Stereo
Features
On-chip 2 preamplifiers
Good ripple rejection owing to on-chip voltage regulator
Minimum number of external parts required
Low noise
8-pin SIP package facilitating easy mounting
Pin-compatible with LA3160
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Specifications
Absolute Maximum Ratings
at Ta = 25C
Parameter
Maximum Supply Voltage
Allowable Power Dissipation
Operating Temperature
Storage Temperature
Symbol
VCC max
Pd max
Topr
Tstg
Conditions
SIP8 22x4.5 / SIP8
Ratings
18
200
20
to
75
40
to
125
Unit
V
mW
C
C
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed,
damage may occur and reliability may be affected.
Recommended Operating Conditions
at Ta = 25C
Parameter
Supply Voltage
Load Resistance
Symbol
VCC
PL
Conditions
Ratings
9
10k
Unit
V
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond the Recommended
Operating Ranges limits may affect device reliability.
Electrical Characteristics
at Ta = 25C, VCC = 9V, RL = 10k, Rg = 600, f = 1kHz, NAB
Ratings
Parameter
Current Dissipation
Voltage Gain
Output Voltage
Total Hamonic Distortion
Input Resistance
Equivalent Input Noise Voltage
Crosstalk
Ripple Rejection
Symbol
ICC
Closed loop
VG
VO
THD
ri
VNI
CT
Rr
Rg = 2.2k
Rg = 2.2k
50
Open loop, VO = 0.77V
THD = 1%
VO = 0.5V
70k
70
1.0
Conditions
min
typ
6.5
35
78
1.3
0.05
100k
1.2
65
40
2.0
0.30
max
8.0
mA
dB
dB
V
%
F
dB
dB
Unit
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be
indicated by the Electrical Characteristics if operated under different conditions.
ORDERING INFORMATION
See detailed ordering and shipping information on page 7 of this data sheet.
©
Semiconductor Components Industries, LLC, 2014
August 2014 - Rev. 0
1
Publication Order Number :
LA3161/D
LA3161
Function of External Parts
C2, C4 are input coupling capacitors. In NAB equalizer amplifier, the gain at low frequencies is high and 1/f noise
inside the IC is emphasized as output noise. Therefore, if the reactance of capacitor at low frequencies is increased,
the dependence of 1/f noise on the signal source resistance causes the output noise voltage to deteriorate, and the
value of reactance must be made small enough as compared with the signal source resistance. C2, C4 also influence
the operation start time and the adequate value of these capacitors is 10F. (Since C2, C4 of less than 4.7F make the
operation start time longer, use C2, C4, of 4.7F or more).
C5, C11 are NF capacitors. The lower cut-off frequency depends on the value of these capacitors.
If the lower cut-off frequency is taken as fL :
C5 (C11) = 1/2 · fL · R2 (R7)
If the value of this capacitor is made larger, the operation start time of amplifier is more delayed. The adequate value
of capacitor is 47F.
The frequency characteristic of the equalizer amplifier depends on C6 and R4, R3 (C10 and R5, R6).
The time constants to obtain the standard NAB characteristic are as shown below.
Tape speed
C6 (R3
R4)
R3 C6
9.5cm/s
3180s
90s
4.75cm/s
1590s
120s
C8 is bias capacitor for the power line. C8 of 47F is inserted at a point as close to the power supply pin (pin 4) as
possible.
C1, C3 are for preventing radio interference in the strong electric field, interference attributable to engine noise, and
blocking oscillation at the time of large amplitude operation. The adequate value of C1, C3 is approximately 1000pF.
C7, C9 are output coupling capacitors. The adequate value of C7, C9 is 10F.
NAB element and determination of gain
Since the DC feedback is provided by R1, R2 of NAB element, which brings about DC output potential at pins 3, 6, it
is impossible to change the value of R1, R2 of NAB element greatly. Therefore, when determining the gain, change
RNF with R1, R2, C1 (NAB element) kept constant.
(1) How to obtain RNF
Impedance Z of NAB element is
1
Z=
+ R2
1/R1 + jC1
1 + jC1{R1 R2/(R1 + R2)}
½
= (R1 + R2)
1 + jC1R1
For a general negative feedback amplifier circuit, A = Ao/ (1 + Ao) applies, and Z = A · RNF is obtained under
conditions of Ao>>A, A>>1 (= RNF/ (RNF + Z), Ao = open-loop gain, A = feedback gain).
Therefore, we can use an approximation of RNF = Z/A.
A = (VG for 1kHz) times, (Set R1, R2 at approximately 100k)
Each time constant of NAB characteristic.
Tape speed
T1 C1, R1
T2 C1 (R1//R2)
9.5cm/s
3180s
90s
4.75cm/s
1590s
120s
(2) Examples of NAB Constants
(a) Tape speed : 9.5cm/s. (8 tracks)
VG : RNF (VG/f = 1kHz)
VG
RNF
30
180
35
100
40
56
dB
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LA3161
(b) Tape speed : 4.75cm/s. (cassette)
VG : RNF
VG
RNF
30
440
35
240
40
130
dB
(c) Flat amplifier
VG : RNF
VG
RNF
30
3.2
35
1.8
40
1
dB
k
Proper cares in using IC
1. Maximum Rating
If the IC is used in the vicinity of the maximum rating, even a slight variation in conditions may cause the maximum
rating to be exceeded, thereby leading to a breakdown. Allow an ample margin of variation for supply voltage, etc.
and use the IC in the range where the maximum rating is not exceed.
2. Short between pins
If the supply voltage is applied when the space between pins is shorted, a breakdown or deterioration may occur.
When installing the IC on the board or applying the supply voltage, make sure that the space between pins is not
shorted with solder, etc.
3. Breakdown of IC attributable to inverted insertion
If the IC is inserted inversely and operated, the IC may suffer from something unusual, thereby leading to a breakdown or
deterioration of the IC. When installing the IC on the board or operating the IC, check the marked surface of IC.
Proper cares to be taken for obtaining optimum operation of IC
Set DC resistance of R1, R2 of NAB element at approximately 100k.
Determine the gain by changing RNF without chaging NAB constant (Refer to Examples of NAB constant.).
VG -- f
VO -- Vi
5
90
3
2
VCC
=
9V
RL
=
10kΩ
Rg
=
600Ω
VG
=
35dB / 1kHz
80
Output voltage, VO -- V
1k
H
3
2
0.1
7
5
3
2
5
0.1
2 3
5
f
=
10
kH
10
5
0H
z
7
Voltage gain,VG --db
1.0
70
60
ort)
F
(100
Ω
sh
00
μ
=
1
)
ort
CNF
sh
0
Ω
(10
μ
F
47
W
ith
NF
VCC
=
9V
RL
=
10kΩ
Rg
=
600Ω
W
ith
ou
tN
FB
z
z
50
40
B
(N
AB
)
30
9.5cm/
s
ec
2 3
5 100K
JK316109
1.0
2 3
5
10
2 3
Input voltage, Vi -- mV
3
2
100
JK316108
3
5
20
2 3 5
100
2 3 5
1K
2 3 5
10K
Frequency, f -- Hz
THD -- VO
VNI -- Rg
INPUT
LA3161
Rg
FLAT
Amp
FILTER
Amp
15Hz to 30kHz
VG
=
45dB
OUTPUT
10
5
3
2
Equivalent input noise voltage, VNI --
μV
Total Harmonic distortion, THD -- %
VCC
=
9V
RL
=
10kΩ
Rg
=
600Ω
VG
=
35dB / 1kHz
2
10
7
5
3
2
VG
=
35dB
=
10kH
z
1.0
5
3
2
0.1
5
3
5
7
0.1
2
3
5
7
VCC
=
9V
RL
=
10kΩ
f
1kHz
100Hz
1.0
7
5
5
7
1
2
3
5
7 10
2
3
5
7 100
2
JK316111
1.0
2
3
Output voltage, VO -- V
JK316110
Signal source resistance, Rg -- kΩ
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